1. Technical Field of the Invention
The invention relates to a disposable self-opener for first opening a tubular bag cartridge and for subsequently squeezing the pasty compound contained therein from the cartridge. Such pasty compounds are used for sealing or gluing joints and have to be squeezed for that purpose through a nozzle onto the site of application. The pasty compound, whether a sealing compound or an adhesive, is packaged in small quantities in disposable plastic cartridges, which are designed in the form of cylinders, whereby the nozzle is mounted at the front end of the cylinder. A plunger can then be pushed into the cylinder from the back, so that the compound is squeezed out through the nozzle. In the case of larger packaging units, plastic one-way cartridges are not suitable because this would create excessively large amounts of waste. Furthermore, plastic is an unsuitable packaging material for many of such pasty products, because the products are poorly durable in plastics. However, an aluminum foil material, or merely a foil coated with aluminum or with aluminum vapors forms a reliable oxygen, light and moisture barrier and assures practically unlimited durability and thus an unlimited shelf life for the products to be packaged. Therefore, many of such pasty products, for example adhesive compound for gluing-in automobile glass panes, or sealing compounds of the type processed in large quantities especially in the field of construction, are commonly packaged in such foil material-like xe2x80x9csausagesxe2x80x9d so as to obtain so-called tubular bag cartridges. Exactly as is done with sausages, the two ends are sealed with metal clips. Such pasty compounds packaged like sausages are offered in xe2x80x9csausagexe2x80x9d sizes of about 10 mm to 100 mm diameter and up to about 50 cm length. To apply the content, such a xe2x80x9csausagexe2x80x9d is inserted in a dispenser device substantially forming a hollow cylinder. A nozzle with a self-opener positioned in front of it can be screwed onto the front side of said cylinder, and a plunger can then be inserted from the back side of said cylinder. Pressure is then directly applied to the foil material from the back end of the xe2x80x9csausagexe2x80x9d . In the disposable case, the nozzle is screwed onto a so-called self-opener, which in turn is inserted in a screw cap and subsequently screwed onto the cylinder end of the dispensing device. Before pasty compounds can be squeezed out, the sausage-like tubular bag cartridge has to be opened after it is inserted in the dispensing device. This occurs as the self-opener is being screwed on because it is also produced in the form of a disposable, plastic injection-molded part, provided on the inside with cutting edges, so that the foil on the front side of the packaging, i.e. at the end of the xe2x80x9csausagexe2x80x9d, is cut open as the self-opener is being screwed on. Under the pressure applied by the plunger, the pasty compound then squeezes through the slits so formed and displaces the foil material sideways. After the pasty compound has been consumed, the foil packaging is removed from the dispenser device and disposed of together with the self-opener and the nozzle.
2. Description of the Prior Art
With the self-openers known heretofore for cutting open the cartridge and mounting the nozzle, it was found to be a drawback that the metal clip of the sausage-like tubular bag cartridge and foil material suspended thereon may tear off under the influence of the flowing pasty compound, and may finally get caught in the opening of the nozzle, where it partly clogs the cross section of the nozzle. With such a partly clogged passage, the compound now exits in the form of a thin xe2x80x9cwormxe2x80x9d having, for example one fourth of the normal diameter. As this requires particularly high plunger pressure and the pressure is to some extent stored in the front part of the pasty compound, the discharge of the compound can no longer be precision-controlled. Once the pressure of the plunger has been relieved, a xe2x80x9cwormxe2x80x9d of pasty compound will continue to exit from the nozzle for a certain period of time. In other words, it is no longer possible to rapidly stop the discharge of the paste. In the worst case, the metal clip torn loose may even clog the nozzle, so that the remaining content of the tubular bag cartridge can no longer be squeezed out and is lost.
Therefore, the problem of the present invention is to create a disposable self-opener that overcomes the drawbacks specified above and permits safe opening of sausage-like tubular bag cartridges containing pasty products, as well as well-dosed and complete squeezing-out of such products by means of a customary dispensing device.
Said problem is solved by a disposable self-opener for opening a tubular bag cartridge and squeezing out a pasty compound therefrom. Said disposable self-opener is comprised of a conical tube shoulder with an orifice, which is produced by injection-molding plastic, whereby the self-opener can be inserted in an associated screw cap and thus screwed onto the end of a tube. On its inner side, the self-opener has gable-shaped pairs of cutting edges with the peak of the gable pointing in the screwing direction. Said self-opener is characterized in that a retainer basket for receiving the metal clip of the tubular bag cartridge to be opened is arranged on its inner side in the center.